I'm not sure if this is necessarily the best way to do this right now, but it mirrors the behaviour in `Twilio::REST::Client` so is at least safe. The issue is that the path variable passed from the `NextGenListResource` to the `TaskRouterClient#get` method was being modified which altered it in the class. This lead to parameters being piled onto the end of an ever growing `@path` variable as more calls were made to `list`.

TaskRouterClient was missing some methods because Client had modules included and TaskRouterClient didn't. Including the Utils and REST::Utils in BaseClient mean both inherited classes get the methods they expect.
Importantly, this means that TaskRouterClient has a url_encode method and can encode url parameters for GET requests. This was being bypassed by the NextGenListResource insisting that the full_path had already been created.
This fixes filter parameters for list resources in TaskRouter which were just dropping their parameters before making the request.